Sunday, April 29, 2007

BSA treatment to improve batch and continuous enzymatic hydrolysis and simultaneous saccharification fermentation

Michael Studer, Bin Yang, and Charles Wyman. University of California, Center for Environmental Research and Technology, 1084 Columbia Avenue, Riverside, CA 92507

The addition of non-catalytic proteins (e.g., bovine serum albumin, BSA) has been shown to enhance cellulose hydrolysis by enzymes or to reduce the necessary cellulase loadings to realize a particular conversion. One plausible explanation is that these additives preferentially attach to lignin and reduce nonproductive binding by enzymes. In the first phase of this study, interactions among substrates, cellulase, and BSA were followed in batch experiments to better understand how these additives influence hydrolysis and simultaneous saccharification and fermentation (SSF). During the second phase, attention is paid to the effect of BSA on continuous hydrolysis and SSF of Avicel and pretreated corn stover. Particular attention is being given to show the effects of BSA and cellulase concentrations, retention time and microorganisms on results. The data from batch and continuous experiments are being compared and conclusions influencing large scale ethanol production are drawn. In addition, a mathematical model is being applied to relate the performance of batch and continuous hydrolysis and SSF to key substrate and enzyme features and identify opportunities to enhance high ethanol yields at lower cost.